CD8A and myeloid sarcoma: Elevated levels of GZMB + Eomes + cytotoxic CD4+ T helper cells in blood and brain infiltrates have recently been associated with progression in multiple sclerosis.44 Another study reported that the GZMB gene expression was increased in CD8+ cells circulating in blood in SP-MS when compared to RR-MS.45 These findings support our theory that the GZMB peak we observed around multiple sclerosis progression could reflect disease progression in multiple sclerosis patients.